X-ray photoelectron spectroscopy (XPS) is known as one of surface analysis methods.
The XPS can acquire information on elements existing in a sample and on a chemical-bonding state by analyzing kinetic energy of photoelectrons that are emitted from a surface of the sample by x-ray irradiation. For example, Patent Document 1 and Non-Patent Document 1 each describe a photoelectron spectroscopy device that includes an electron gun for generating a focused electron beam, an anode for generating X-rays by incidence of the focused electron beam, a focusing means for focusing the X-rays generated in the anode to the surface of a sample, and an analyzer means for analyzing energy of photoelectrons that are emitted from the surface of the sample by X-ray irradiation.
In this type of conventional X-ray analysis device, it has been desired to irradiate X-rays having appropriate energy depending on a sample or the purpose of analysis. For example, Patent Document 2 and Non-Patent Document 2 describe an X-ray spectroscopy device and an X-ray analysis device, including a spectrometer means capable of selecting a plurality of X-rays having different energy in a single device, but it has been considered impossible that a single device adjusts the energy in a wide range and focuses X-rays to the surface of the sample.
Further, it is theoretically known that a non-destructive analysis in a depth direction can be performed by an analysis of spectra of photoelectrons having different take-off angles, depending on the energy of the X-rays. In the current X-ray analysis device, however, the depth of detection is limited to no more than about several nm because photoelectrons are scattered in the sample. For that reason, this theory has been considered to be irrealizable.    Patent Document 1: Japanese Patent Application Laid-open No. Hei 7-325052    Patent Document 2: Japanese Patent Application Laid-open No. 2001-133421    Non-Patent Document 1: Masaaki Kobata et al., “Development of the Hard-X-ray Angle Resolved X-ray Photoemission Spectrometer for Laboratory Use”, ANALYTICAL SCIENCES FEBRUARY 2010, VOL. 26, pp. 227-232 (2010)    Non-Patent Document 2: X-ray fluorescence analysis device with high count rate and high resolution (OURSTEX Corporation), http://business.atengineer.com/ourstex/product3.htm    Non-Patent Document 3: J. A. Berden: “X-Ray Wavelengths”, Review of Modern Physics, Vol. 39, No. 1, pp. 78-124 (1967)